Texture2D::getRenderTarget does not assume that needsRenderTarget succeeded....

Texture2D::getRenderTarget does not assume that needsRenderTarget succeeded.

Specifically, it checks that mTexture is not null.

This is to fix this crash that has been happening out in the wild:

0x01444822 	[libGLESv2.dll 	- texture.cpp:1417] 	gl::Texture2D::getRenderTarget(unsigned int)
0x01445615 	[libGLESv2.dll 	- texture.cpp:2048] 	gl::Texture::TextureColorbufferProxy::getRenderTarget()
0x01453bb0 	[libGLESv2.dll 	- context.cpp:1579] 	gl::Context::applyRenderTarget(bool)
0x01455395 	[libGLESv2.dll 	- context.cpp:2413] 	gl::Context::clear(unsigned int)
0x014460c4 	[libGLESv2.dll 	- libglesv2.cpp:611] 	glClear
0x01c53b75 	[chrome.dll 	- gles2_cmd_decoder.cc:3021] 	gpu::gles2::GLES2DecoderImpl::ClearUnclearedRenderbuffers(unsigned int,gpu::gles2::FramebufferManager::FramebufferInfo *)
0x01c53cee 	[chrome.dll 	- gles2_cmd_decoder.cc:3078] 	gpu::gles2::GLES2DecoderImpl::DoFramebufferTexture2D(unsigned int,unsigned int,unsigned int,unsigned int,int)
0x01c57c7d 	[chrome.dll 	- gles2_cmd_decoder_autogen.h:756] 	gpu::gles2::GLES2DecoderImpl::HandleFramebufferTexture2D(unsigned int,gpu::gles2::FramebufferTexture2D const &)
0x01c52197 	[chrome.dll 	- gles2_cmd_decoder.cc:2214] 	gpu::gles2::GLES2DecoderImpl::DoCommand(unsigned int,unsigned int,void const *)
0x01c4fa78 	[chrome.dll 	- cmd_parser.cc:56] 	gpu::CommandParser::ProcessCommand()
0x01c4f8ba 	[chrome.dll 	- gpu_processor.cc:100] 	gpu::GPUProcessor::ProcessCommands()

It was a Windows XP service pack 3 box with Chrome 7.0.524.0. ANGLE was at r418 in this build. I suspect it attempted to glClear after a device lost, which caused needsRenderTarget to fail.

This will hopefully patch it up so it doesn't crash. We'll need to check we aren't assuming mTexture is not null elsewhere.

[apatrick1, 2010-09-16 20:36:54]

A quick one. But can you take a look and see if you agree that this was a device
lost issue and, if so, whether there are any other issues with dereferencing
mTexture when it is null after a device lost?

Thanks

Al

[dgkoch, 2010-09-17 19:49:22]

Hi Al,

It seems fairly likely that this is a lost device issue.  

I think more than this will be necessary to ensure that there are no
dereferences of a null mTexture.   Not to mention you also need to make sure to
check the result from getRenderTarget then as well.

So.. this is a start, but at a minium, you'd want exactly the same fix in
TextureCubeMap::getRenderTarget.

We'll do an audit pass over Texture.cpp looking for similar issues.

Daniel